REFERENCES Boyden, C. R. B. (1971). Intertidal fauna of Lundy. In: Hiscock, K. (ed.) (1971). Report on the proposal to eastablish a marine nature reserve around Lundy, Marine Biological investigations 1971. Published by the Lundy Field Society 66 pp. Harvey, L.A. (1950). The granite shores of Lundy. Rep. Lundy Fld Soc., 4, 34-44. Hiscock, K. ( 1974). The marine fauna of Lundy. General Introduction. Rep. Lundy Fld Soc., 25, 16-19. King, P . K. (1974). British sea spiders. Synopses of the British Fauna (New Series) 5. London: Linnaen Society, 68 pp.

Rep. Lundy Fld Soc. 27 (1976). THE MARINE FAUNA OF LUNDY OPISTHOBRANCHIA

GREGORY H. BROWN Department of Zoology, The University, Bristol & PETER J. HUNNAM Dale Fort Field Centre, Dale, Have1/ordwest, Dyfed INTRODUCTION The opisthobranchs of sea areas to the south-west of England have received relatively close scrutiny in recent years. Advances in understanding the system­ atics and ecology of these have been possible as a result of numerous specimens collected by SCUBA divers. This has led to two publications which will be of assistance in the study of specimens from Lundy. Hunnam & Brown (1975) list and describe from the Dale peninsula which is thought to be hydrographically 'downstream' from Lundy, while Thompson & Brown (1976) describe all valid species known from the British Isles with information on ecology and distribution. Future collections will undoubtedly supplement the Lundy List but it was felt necessary to publish at the present time as several new records for the Bristol Channel and one new record for Great Britain are included. A total of 47 species are listed. Ten species from nearby localities, as yet unknown from Lundy, are mentioned in an addendum. SAMPLING AND COLLECTING METHODS The abundance of several species, and the necessity to search particular habitats for others, precluded the possibility of an accurate quantitative survey. In order to maximize the precious time underwater spent in searching all available prey species, other recording was unavoidably coarse. Abundance was estimated on a one to three scale and substrate types were split into four categories. Obser­ vations on the surface and information from nautical charts enabled the assess­ ment of maximum current speeds and exposure to wave action. Dives were standardized at 15-20 minutes duration on sites spread around the island at various depths ranging from 0 to 30 metres below C.D. As only epifaunal forms are readily available to a diver, it is probable that further infaunal opistho­ branchs, especially bullomorphs, will be collected using dredging techniques. DISTRIBUTION The close relationship between the opisthobranchs and their food species is well known. Various authors have likened it to a parasitic association. Thompson (1964) showed that certain larvae will only settle and metamorphose on the prey species. Opisthobranch distribution is therefore expected to mirror the dis-

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"'0' c: Do to fragilis ...... ::I Nemertesia anten!'l.in.."l 0. Do to pinna ti!'ida ___ and N. ramos ~ ··· ·-······- · · ··· ··· ~ • I ··· ··· ····· ·-·· Do to corona ta "';;;; · calyptoblas tic hytlroids Coryphella peda ta ::;•. -.."':":.1- ·· · ·:· · ·-····.·· . ·.~: ...... 0 hydro ids Pacelina annulicornis ···.····· · · · ·····•· · · ·· ·· · ·· · · · ···· hydroids 3 l'avoririus blianus ·---···-··-· other nudibranchs 0 spawn of @ ----···---········ ~.. I) Tri toni a odhneri Eunicella verru.cosa !" 0 0 Depth r a nge· 5 5 oi d1.ve s in II metres below C .D. 10 rlrrlJir 1 I ri nriiil 15 15 2 riiiiilr 20 ~IIILIIlr 25 I I 25 !:.l:.: .:: l - 2 • 3 - 10 -E---J.~ A -E- B ~C~'"'"- B ~-E--- C ___.._D...,. A = granite bedrock with gul.lie3 , eli ffs and over h..:lnd or silt. tribution of the prey species. Fig. 1 shows the results for those species collected at six or more sites. The primary consideration in any conclusions drawn from these data must be that the study was concentrated into a two-week period in one particular year. The seasonal and annual variation will only become apparent when future surveys are completed. The results, taken as a whole, show that opisthobranchs are to be found all around the island although certain species predominate in certain areas. Strong­ current and wave-exposed, west coast situations supported the growth of large patches of indivisa and T. larynx whose presence is indirectly indicated in Fig. 1 by the prey species , and Face/ina coronata. Nemertesia antennina, and to a lesser extent N. ramosa, were present at nearly all localities below 10 m, excepting the very strong current areas. Forty Nemertesia colonies were inspected during a dive near Gull Rock, 65% of which were found to have attached adults or spawn of fragilis or D. pimzatifida. Large colonies of Eunicella verrucosa bearing odhneri were commonly encountered below 15m along a stretch of the east coast from Brazen Ward to Halfway Wall Bay. Two belt transects, each of approximately 60 m' were marked out and inspected, running from shallow to deep (25 m) water near Brazen Ward. Within these transect areas a total of 36 gorgonian colonies were encountered, of which II had T. odhneri adults or spawn attached. On these II colonies were found 22 spawn masses and 25 adults, ranging between 14 and 34 mm in length. Sublittoral surveys carried out around Skomer in Pembrokeshire have indicated that divers can have a drastic effect on 'souvenir' species. The sea fan, Eunicel/a, is favoured by many collectors because of its delicate shape and colour as well as its rarity. Hiscock (1974) suggests that the growth rate is little more than I em per year which is of little comfort to conservationists interested not only in the sea fan but also intimately associated species. Tritonia odlzneri has never been found away from Eunicella verrucosa and the perfect mimicry of the nudibranch indicates that this species is restricted to living solely on this prey species. E. verrucosa was found less frequently on the west coast but here too, T. odhneri was found grazing on some of the colonies. Algal distribution is important not only to the herbivores but also to those species feeding on encrusting polyzoans attached to the algae; Limacia clavigera feeds on Electra pi/osa often encrusting on Delesseria sanguinea and quadri/ineata feeds on Membranipora membranacea encrusting on Laminaria spp. The only nudibranch distribution which cannot be readily explained as equivalent to the prey distribution, is that of Favorinus blianus. Twenty-seven specimens were collected, all from the sheltered east coast. This species is known to eat eggs of other nudibranchs including species found spawning prolifically on the west side. Both in numbers of individuals and variety of species, the dorid nudibranchs feeding on polyzoans were well represented all around the island but especially at sites with only a moderate maximum current. Sponge-eating dorids were rarely obtained indicating either the true situation or a failing in the search technique which is not apparent. Hydroid-eating aeolids and dendronotaceans were abundant only in the fast current areas and on the exposed west coast, with the one exception of Doto spp. on Nemertesia spp. already mentioned.

RARE SPECIES The supposedly rare species, maculata, Face/ina annulicornis, Favorinus blianus, Greilada e/egans and Polycera faeroensis are now known to be well established to the south-west of England (Hunnam & Brown, 1975) and will not be included here. Species collected around Lundy warranting special mention are : Colpodaspis pusilla M . Sars, 1870 (Fig. 2D). This is only the second British record following its collection near Plymouth by Garstang in 1893. Garstang was dredging in 30 m of water over red sandstone but the Lundy specimen was 39 D

Fig. 2. Rare species of opisthobranchs found around Lundy: A, Tritonia odhneri, dorsal view: pink body with lighter areas around the rhinophores and branchiae. B, the same, adults and spawn attached to Eunicella verrucosa. C, Trinchesia sp., dorsal view: translucent white body with yellow overlain with white pigment patches. D, Colpodaspis pusilla, dorsal view: white body with white powdery pigment on the rhinophores. E, pal/ida, dorsal view: trans­ lucent white body with glistening white pigment on all projections. in shallow water creeping over the red alga, Delesseria. Detailed examination is in progress of the little-known anatomy. Lemche has recorded another specimen from S.W. Eire, also taken in June, 1975 (personal communication). Tritonia odhneri (Tardy, 1963) (Fig. 2A & B). The finding of this elusive species on Lundy caused great elation. The eventual capture followed years of inspecting every Eunicella colony encountered by the authors. First described from the Atlantic coast of France (l'ile du Re) in 1963, it has only been accurately recorded once elsewhere (from S.W. Eire). Photographs taken of a mis-identified Tritonia from the Channel Isles also proved to beT. odhneri on re-examination. Since the Lundy collection, it has been discovered off N. Cornwall. As is often the case, the presence of these animals was given away by the spawn, a thin pink thread wound around the axial rod of the gorgonian. The adults were impressively cryptic, both in coloration and body form as the dorsal branchiae mimic the extended polyps. The pose adopted in the field is either tightly wrapped around the branches of the Eunicella verrucosa colony or attached merely by the meta podium thus resembling yet another bifurcation of the prey (Fig. 2B). A white variety of E. verrucosa (possibly not a variety but the white Medi­ terranean species E. stricta) is found around Lundy (Hiscock, 1974) and it was hoped to find white specimens of the nudibranch predator but, as yet, the search has been unsuccessful. A parallel, though opposite, adaptation has been observed in the normally white prosobranch cowry, Simnia patula. This species is well camouflaged on the white Alcyonium digitatum and the rare white Eunicella. Pink Simnia were, however, found on the pink forms of E. verrucosa and further improved their camouflage by producing branching papillae from the mantle surface. Trapania pallida Kress, 1968 (Fig. 2E). First described in 1968 from near Ply­ mouth, this species has since been found at Roscoff (Bay of Biscay), at Mullion Cove (S. Cornwall) and now Lundy. Little is known of its mode of life but a close relative, T. maculata Haefelfinger, 1963, found only once around Britain (Brown & Picton, 1976) is thought to feed on Chartella papyracea. Trinchesia sp. (Fig. 2C). A full description is in preparation and will be published elsewhere. This small yellow aeolid is considered to be a new species. The radula and overall appearance are similar to Trinchesia pustulata but it lacks the charac­ teristic pustules described by Alder & Hancock (1845-55). A single specimen was found in 1971 while diving in St Brides Bay. Numerous examples have now been collected around Skomer Island (Pembs) and off Watermouth Cove (N. Devon). The prey of specimens from Pembrokeshire was identified as Halecium muricatum. THE LIST All site names are taken from the map of Lundy published in the introduction to this series (Hiscock, 1974). Unless otherwise initialled, all records refer to collections made by the authors during a two-week period, 22nd June to 6th July, 1975. Also included are records of shore collections from 1948 to 1950 by L. A. Harvey (LAH) and underwater collections by K. Hiscock (KH) and J. Ilott (JI) from 1971 to 1974, later identified or verified by one of the authors (GHB). The source of nomen­ clature for all the species, except the pyramidellid, Odostomia eulimoides, is Thompson and Brown (1976). Synonyms used in recent publications are listed. ('Marine Biological Association, 1957' is abbreviated to 'MBA, 1957'). The overall abundance of specimens encountered during the two-week period is indicated by the terms 'sparse', 'common' and 'abundant' referring to total collections of 2-10, 11-30 and 30+ respectively. Depths are given in metres (m) below Chart Datum. Phylum Class Subclass OPISTHOBRANCHIA Order PYRAMIDELLOMORPHA Family PYRAMIDELLIDAE Odostomia eulimoides (Hanley, 1844) 41 [Graham, 1971,p. 106] Lundy Roads, 20m, heavy infestation on the scallop, Pecten maximus. Order BULLOMORPHA Family DIAPHANIDAE Colpodaspis pusilla (M. Sars, 1870) (Fig. 2D) Knoll Pins, 5 m, one specimen creeping over the red alga Delesseria. The diet, anatomy and details of the life history are all unknown. (See section on RARE SPECIES.) Family PHILINIDAE Philine punctata (Adams, 1800) Halfway Wall Bay, 15m, single specimen; Knoll Pins, 10.7.75 (KH), two specimens. Although rarely recorded, it is said to fa vour shallow silty sand and is widely distributed around the British Isles. Order APLYSIOMORPHA Family APLYSIIDAE Aplysia punctata Cuvier, 1803 Intertidal (LAH); Lee Rocks, Long Roost, Ladies Beach, in all cases less than 10m depth. Adults and spawn common amongst and upon red algae. Order SACOGLOSSA Family ELYSIIDAE Elysia viridis (Montagu, 1804) Intertidal (LAH); Landing Bay Beach, intertidal, single specimen collected on green alga. Order NUDIBRANCHIA Suborder DENDRONOTACEA Family Tritonia hombergi Cuvier, 1803 Lundy Roads, 6.8.74 (KH); St Mark's Stone, 20m, single specimen on Alcyonium digitatum although this food species was abundant at many fast current sites.

Tritonia lineata Alder & Hancock, 1848 /ineata: (MBA, 1957; Miller, 1961) Gannets Rock, Gannets Rock Pinnacle, Knoll Pins, 10- 20 m, sparse collections and never on any identifiable food species although probably an alcyonacean. Tritonia odhnerl (Tardy, 1963) Duvaucelia odhneri: (Tardy, 1963) Long Roost, from Brazen Ward to Halfway Wall Bay, 15-25 m, specimens always on Eunice//a verrucosa which was common at the latter sites. Spawning. (See section on RARE SPECIES.) Tritonia plebeia Johnston, 1828 Duvaucelia plebeia: (MBA, 1957; Miller, 1961) Battery Point, 15m, only a single specimen collected, probably because the search of likely habitats is prevented until the diet becomes known. Family DENDRONOTIDAE Dendronotus frondosus (Ascanius, 1774) Hen and Chickens, Black Rock, Lee Rocks, Long Roost, north of Rat Island, south-west of Surf Point, 5-20 m, in all cases on Tubu/aria indivisa which was not found in sheltered parts of the east coast. None of the common (locally abundant) specimens were in excess of 25 mm in length, although this species is known to reach lengths of more than 100 mm: 42 Family DoTOJDAE Doto coronata (Gmelin, 1791) Common all around the island, intertidal to 25 m, found on a variety of calyptoblastic hydroids but particularly Obelia geniculata attached to the fronds of Laminaria. Spawning. Doto fragilis (Forbes, 1838) Quarry Bay, 19m, 6.8.71 (KH); extremely abundant all around the island, 5- 25 m. The heaviest infestation of the two prey species, Nemertesia antennina and N. ramosa was on the east coast from Gannets Rock to Gull Rock. Spawning. Doto pinnatifida (Montagu, 1804) Common on both east and west coasts, 5-25 m. This species was far less abundant than D. fragilis but shared the same two prey species. Spawning. Family marmoratus (Alder & Hancock, 1845) Lomanotus genei: (MBA, 1957; Miller, 1961) Lomanotus flavidus: (MBA, 1957) Needle Rock, Half Tide Rock, Gull Rock, 10-20 m. Only juveniles less than 10 mm in length (maximum size is 55 mm), all on Nemertesia antennina. Suborder Family Goniodoris nodosa (Montagu, 1808) Intertidal on Rat Island, (LAH); StJohn's Stone, 20m, single specimen on Alcyonidium gelatinosum. Ancula cristata (Alder, 1841) Knoll Pins, 6. 7. 74 (JI); Half Tide Rock, Jenny's Cove, I 0 m, sparse. Trapania pallida Kress, 1968 (Fig. 2E) Knoll Pins, 6.7.74 (Jl); Gannets Rock, Gannets Rock Pinnacle, Knoll Pins, Gull Rock, Halfway Wall Bay, 10-20 m. A total of twelve specimens were seen, usually on Chartella ( = Flustra) papyracea. (See section on RARE SPECIES.) Family 0NCHIDORIDIDAE Onchidoris luteocincta (M. Sars, 1870) Diap!wrodoris luteocincta: (Miller, 1961) Knoll Pins, 6.7. 74 (JI); very common all around the island, 5-25 m. Acanthodoris pilosa (Muller, 1789) Gannets Rock, 20m, a single specimen on Alcyonidium gelatinosum. Family TRIOPHIDAE Crimora papillata Alder & Hancock, 1862 Needle Rock, 20m. This was considered as a rare species until1972, since when vast numbers have been collected by divers around the south-west of England. However, only one specimen was recorded from Lundy, this being found on Chartella papyracea, the usual prey species. Family NoroooRIDIDAE Aegires punctilucens (Orbigny, 1837) South-west of Surf Point, 15 m, single specimen. Diet unknown. Family Polycera faeroensis Lemche, 1929 Abundant from the Knoll Pins, 6.7.74 (JI); extremely abundant all around the island, 5-25 m. Crisia denticulata would appear to be a favourite diet although other polyzoans cannot be excluded. Specimens measured up to 43 mm in length, the largest yet recorded. Spawning profusely. 43 (Miiller, 1776) Gannets Rock, 10m, 29.7.74 (KH); Hen and Chickens, Black Rock, Lee Rocks, Surf Point and shallower sites all around the island, intertidal to 15 m, abundant on Membranipora membranacea on the fronds of Laminaria. A variety was also present which was covered in small black specks as well as yellow and orange spots. Intermediates were found between these and the orthodox speci­ mens. Spawning. Greilada elegans Bergh, 1894 Battery Point, 20m, 4.8.71 (KH); Knoll Pins, 6.7.74 (JI); common in deeper water (15-25 m) throughout the exposed west side of the island. On the east side it was present at the Knoll Pins and Gull Rock. The polyzoan on which adults and spawn were found, was flabella fa. Thecacera pennigera (Montagu, 1815) Intertidal (LAH); St James's Stone, Battery Point, Half Tide Rock, Gull Rock, 15-25 m, spawn and adults common on Bugulaplumosa. Limacia clavigera (Miiller, 1776) Euphurus claviger: (MBA, 1957) Intertidal (LAH); Knoll Pins, 6.7.74 (JI); common on the east side and at Lee Rocks, 5-20 m, spawning adults on Electra pilosa encrusting on red algae.

Family ROSTANGIDAE Rostanga rubra (Risso, 1818) Rostanga rufescens: (MBA, 1957; Miller, 1961) Lee Rocks, Surf Point, 20 m, two specimens only.

Family DORIDIDAE Doris maculata Garstang, 189 5 Doridigitata sticta: (MBA, 1957) Lee Rocks, Needle Rock (spawn only), 15m. The single adult found makes Lundy only the third known location for this species around Great Britain. It has been previously collected near Plymouth and around Skomer, Pembrokeshire. Family Cadlina laevis (Linnaeus, 1767) Knoll Pins, 6.7.74 (JI); Hen and Chickens, Lee Rocks, St Mark's Stone, Dead Cow Point, Half Tide Rock, H.M.S. Montagu, Gull Rock, 10-20 m. Although present at many sites around the island, this species was not in great abundance in any one spot. Family ARCHIDORIDIDAE Archldoris pseudoargus (Rapp, 1827) Intertidal (LAH, as A. brittanica); Knoll Pins, 20m, 10.8.74 (KH); Lee Rocks, 10m, single specimen.

Suborder ARMINACEA Family ANTIOPELLIDAE (Chiaje, 1841) cristatus: (MBA, 1957; Miller, 1961) Extremely abundant, very large specimens were located throughout the east coast. Sparse records were obtained from the Knoll Pins and Gull Rock, 10-25 m Individual specimens measured up to 75 mm in length compared to the previously recorded maximum of 55 mm. Adults and spawn were frequently seen on Bugula jfabellata although spawn was also attached to Alcyonidium gelatinosum.

44 Suborder AEOLIDIACEA Family CoRYPHELLIDAE Coryphella verrucosa verrucosa (M. Sars, 1829) This was the most abundant species encountered by the authors during the survey. It was present in inestimable numbers on , which was often dense on the numerous wrecks, as well as on the granite substrate in strong current situations. On the east coast, it was only found in abundance at Gannets Rock and Gannets Rock Pinnacle where the diet appeared to be the smaller Tubu/aria larynx. Spawning. Coryphella lineata (Loven, 1846) Long Roost, Needle Rock, Half Tide Rock and Gannets Rock Pinnacle, 10- 25 m. Although easily distinguished from C. verrucosa by the white lines on the body, some authors have considered this species to be a variety of C. verrucosa. Certainly the lines on the cerata may be very feint in some specimens and C. lineata was found in the field only at sites where C. verrucosa was present in greater numbers and feeding on the same prey species. Until a lot more evidence is discovered, however, these two forms must be recorded separately and it should be noted that C. lineata is present in the Mediterranean whilst C. verrucosa is not. Coryphella pedata (Montagu, 1815) Common throughout the east coast, at Lee Rocks and Surf Point. Single specimen from the Knoll Pins. Collected from depths between I 0 and 25 m. Spawning. Family Facelina annulicornis (Chamisso & Eysenhart, 1821) Face/ina punctata: (MBA, 1957) Knoll Pins, 15m, 2.8.71 (KH); Half Tide Rock, from the Knoll Pins to Quarry Bay and to the south-west of Surf Point, 10- 20 m. Common and spawn­ ing.

Facelina auriculata coronata (Forbes & Goodsir, 1839) Face/ina auriculata longicornis: (Miller, 1961) Face/ina coronata: (MBA, 1957; Hunnam & Brown, 1975) Hen and Chickens, Lee Rocks, Surf Point, Long Roost, St James's Stone, Needle Rock and Gull Rock, 15-25 m. The spawn and adults were usually found on Tubularia indivisa attached to wreck material.

Facelina auriculata curta (Alder & Hancock, 1843) Face/ina auriculata drummondi: (Miller, 1961; MBA, 1957) Face/ina curta: (Hunnam & Brown, 1975). Knoll Pins, 6.7.74 (JI); Gull Rock, 18m, a single specimen.

Family FAVORINIDAE Favorinus blianus Lemche & Thompson, 1974 Common from Brazen Ward to North Quarry, 15-25 m. In the laboratory these animals fed on the spawn of Polycera faeroensis and Greilada elegans. The eggs pass into the digestive diverticula within the cerata and maintain their colour for several days. Specimens feeding on the orange spawn of Greilada elegans soon became a brilliant orange themselves. Spawning. Favorinus branchialis (Rathke, 1806) Gull Rock and to the north of Mouse Island, 5-20 m, sparse but spawning. Family AEOLIDIIDAE papillosa Cuvier, 1798 Kittywake Gulley, 8 m, a single specimen.

45 Family CtrTHONIDAE Tergipes tergipes (Forskal, 1775) Tergipes despectus: MBA, 1957; (Miller, 1961) Montagu Steps, 5 m. This is a very small, inconspicuous animal, requiring meticulous searching if it is to be found. Although only collected from one site, it is probably common on Obelia geniculata attached to Laminaria fronds in shallow water all around the island. Catriona aurantia (Alder & Hancock, 1842) Trinchesia aurantia: (MBA, 1957; Miller, 1961) Fast current situations to the north and south of the island, 10-25 m. All specimens were juveniles less than 5 mm in length (maximum size is 21 mm), feeding on Tubularia indivisa. Trinchesia caerulea (Montagu, 1804) Gull Rock, 15m, a single specimen. Trinchesia sp. (Fig. 2C) Half Tide Rock, Gannets Rock, 15-20 m. Six specimens and spawn were obtained, all on Halecium muricatum. (See section on RARE SPECIES.) Family exiguus (Alder & Hancock, 1848) Montagu Steps, 5 m. As on Lundy, this species is very often to be seen with Tergipes tergipes on Obelia geniculata and other small calyptoblastic hydroids. Our solitary record is doubtless a result of inadequate sampling of this habitat as Hiscock (1974) says Obelia is common all around the island. Spawning. Eubranchus pallidus (Alder & Hancock, 1842) The juvenile specimens (all less than 5 mm in length) were abundant at many sites in association with Tubularia indivisa. Adults are known to feed on this gymnoblast but it is likely that these juveniles were taking the smaller epizoitic calyptoblasts such as Sarsia eximia and Garveia nutans. One adult measuring 23 mm was found near Black Rock. Forbes, 1838 Black Rock, Hen and Chickens, 20-25 m. As was the case with E. pallidus, nearly all the specimens of E. tricolor were juveniles less than 5 mm (maximum size is 45 mm) and they were found in association with Tubularia indivisa or the epizoitic calyptoblasts.

ADDENDUM The very nature of opisthobranch dispersal, usually by larvae in the at the mercy of wind-driven currents for several days or weeks, suggests that the species list may vary considerably from year to year or even from one season to the next. The ten species listed below are well known in recent years from nearby localities and could be expected in future collections from Lundy. Goniodoris castanea (Alder & Hancock, 1845). Known from the Irish Sea• Skomer Island and Milford Haven (Pembrokeshire) and S. Cornwall. Okenia elegans (Leuckart, 1828). Known from Skomer Island and Milford Haven (Pembrokeshire) and S. Cornwall. Onchidoris bilamellata (L. 1767) ( = 0. fusca). Known from Pembrokeshire, the Bristol Channel and S. Cornwall. Onchidoris muricata (Muller, 1776). Known from Pembrokeshire, the Bristol Channel and S. Cornwall. Adalaria proxima (Alder & Hancock, 1845). Known from the Bristol Channel.

46 Palio dubia (M. Sars, 1829) ( = Polycera dubia). Known from Skomer Island (Pembrokeshire), the Gower Peninsula, N. and S. Cornwall. Discodoris planata (Alder & Hancock, 1846) ( = Archidoris stellifera, = Geito­ doris planata). Known from Skomer Island (Pembrokeshire) and S. Cornwall. Jorunna tomentosa (Cuvier, 1804). Known from Skomer Island (Pembrokeshire), N. Devon and S. Cornwall. Trinchesia amoena (Alder & Hancock, 1845) ( = Cuthona amoena). Known from Skomer Island (Pembrokeshire), the Gower Peninsula, N. Devon and S. Cornwall. Eubranchus farrani (Alder & Hancock, 1844). Known from Skomer Island (Pembrokeshire), N. Devon, N. and S. Cornwall.

REFERENCES Alder, J. and Hancock, A. (1845-55). A Monograph of the British Nudibranchiate Mollusca. Ray Society, London. 369 pp. Brown, G . H. and Picton, B. E. (1976). Trapania macula/a Haefelfinger, a doridacean nudibranch new to the British fauna, J. Conch, 29, 63-65 Graham, A. (197 I) British Prosobranchs. Synopses of the British fauna (New Series), No. 2. Linnean Society, London. Harvey, L.A. (1950). The granite shores of Lundy. Rep. Lundy Fld Soc., 5, 34--44. Hiscock, K. (1974). The marine fauna of Lundy. General introduction. Rep. Lundy Fld Soc., 25, 16-19. Hiscock, K. (1974). The marine fauna of Lundy. Coelenterata. Rep. Lundy Fld Soc., 25, 20-32. Hunnam, P. J. and Brown, G. H. (1975). Sublittoral nudibranch mollusca (sea slugs) in Pembrokeshire waters. Fld Stud., 4, 131-159. Marine Biological Association (1957). Plymouth Marine Fauna. Third Edition. Marine Biology Association of the United Kingdom, Plymouth, 457 pp. Miller, M . C. (1961). Distribution and food of the nudibranchiate mollusca of the Isle of Man. J. Anim. Ecol., 30, 95-116. Tardy, J. (1963). Description d'une nouvelle espece de Tritoniidae: Duvaucelia odhneri, n!coltee sur Ia cote atlantique fran<;:aise . Bull. !nsf. oceanogr. Monaco, 60, No. 1260, 10 pp. Thompsoq, T. E. (1964). Grazing and the life cycles of British nudibranchs. In: Grazing in Terrestrial and Marine Environments, British Ecological Society Symposium No.4, ed. D. J. Crisp, Blackwell, Oxford, 275-297. Thompson, T. E. and Brown, G. H. (1976). British Opisthobranch Molluscs Synopses of the British fauna (New Series}, No 8. Linnean Society, London

47